Impact gun and method of forming a structural connection

ABSTRACT

AN IMPACT GUN ADAPTED TO DEFORM THE TUBULAR END OF A FASTENER SECURED TO A SUPPORT, INCLUDING A PLUNGER MEANS SUPPORTED FOR RECIPROCATING MOVEMENT BY THE BODY PORTION OF THE GUN HAVING A SPECIALLY DESIGNED HEAD PORTION ADAPTED TO ENGAGE THE INNER EDGE OF THE FASTENER AND DE FORM THE TUBULAR END RADIALLY OUTWARDLY AND TOWARD THE SUPPORT. THE HEAD PORTION OR ANVIL IS INITIALLY SEPARATED FROM THE PLUNGER OR HAMMER, AND IS GUIDED INTO CONTACT WITH THE END OF THE FASTENER BY A PILOT SUPPORTED FOR RECIPROCATION WITHIN THE HEAD PORTION. THE METHOD DISCLOSED HEREIN INCLUDES DISPOSING A SUPPORTING MEMBER WITHIN THE TUBULAR FASTENER AND IMPACTING THE FASTENER END.

E. A. MEYER STRUCTURAL CONNECTION 2 Sheets-Sheet l INVENTOR E/Vfiflfif/FTA M15767? ATTORNEYS fiat, 1&9, 171

' IMPACT GUN AND METHOD OF FORMING A Filed Dec. 51, 1968 Oct. 19, 19 111 E, A, MEY R 3,613,431

IMPACT GUN AND METHOD OF FORMING A STRUCTURAL CONNECTION Filed Dec. 31, 1968 2 Sheets-Sheet 2 TEE-=5 90 64 '70 as 74 l 3 I E25 94 I "3 1 92 64 INVENTOR ATTORNEYS United States Patent US. Cl. 72-369 11 Claims ABSTRACT OF THE DISCLUSURE An impact gun adapted to deform the tubular end of a fastener secured to a support, including a plunger means supported for reciprocating movement by the body portion of the gun having a specially designed head portion adapted to engage the inner edge of the fastener and deform the tubular end radially outwardly and toward the support. The head portion or anvil is initially separated from the plunger or hammer, and is guided into contact with the end of the fastener by a pilot supported for reciprocation within the head portion. The method disclosed herein includes disposing a supporting member within the tubular fastener and impacting the fastener end.

SUMMARY OF THE INVENTION The impact gun of this invention is particularly, although not exclusively adapted to deform the generally tubular end of a fastener secured to a support, such as the fastener shown in my co-pending application for United States Letters Patent, Ser. No. 762,549. The fastener disclosed in the above referenced application for patent is generally cylindrical, and includes a tubular end which is deformed radially outwardly and toward the support to secure a structural member received on the support. The impact gun of this invention includes a plunger means supported for reciprocating movement by the body portion of the gun.

The plunger includes a head portion adapted to deform the open end of the fastener. In the preferred embodiment of this invention, a pilot is supported for reciprocating movement within the head portion, generally co-axial therewith, having an end extending beyond the impacting end of the head portion. The end of the pilot is received within the tubular end of the fastener to guide the impacting head portion of the gun into contact with the fastener. In the disclosed embodiment, the pilot is spring tensioned toward the forward end of the gun, and retractable against the force of the spring to guide the head portion into proper orientation with the fastener. The spring in the disclosed embodiment is a coil spring tensioned between the rearward end of the pilot and the head portion.

The head portion of the plunger in the preferred embodiment is initially isolated or separated from the plunger or hammer, and serves as an anvil to deform the fastener. The head portion or anvil may also be normally spring tensioned toward the forward end of the gun to eliminate unwanted movement, and reduce the shock of impact. In this embodiment, the head portion is also retracted into the body portion of the gun prior to impact by the hammer or plunger.

The impacting end of the anvil has been specially designed to deform the tubular end of the fastener shown and described in the above referenced co-pending application for United States Letters Patent. The prior art discloses a number of riveting tools having a concave annular impacting surface, terminating at the radial outer edge of the anvil. These designs however have been found unsatisfactory for the impacting gun of this invention, because the tubular end of the fastener tends to bind or jam in the concave surface. This problem has been eliminated by the disclosed design.

In the preferred embodiment of this invention, the impacting end of the anvil includes a central portion adapted to be received within the open end of the fastener having an annular concave surface adapted to engage the inner edge of the tubular fastener to deform the end of the fastener radially outwardly from its axis and toward the support. The pilot, included in the preferred embodiment, is disposed in an aperture coaxial with the axis of reciprocation of the anvil, and extends beyond the impacting end. The annular concave surface smoothly blends into an outer annular surface which is substantially flat and generally perpendicular to the reciprocating axis of the anvil to reversely fold over the tubular end of the fastener toward the support. In one of the disclosed embodiments, the outer annular surface is slightly tapered from the axis of the head portion, away from the impacting end, to define a generally conical surface. An angle of approximately five degrees has been found very satisfactory.

In the operation of the impact gun of this invention, the forward end of the pilot is first disposed within the open end of the fastener. The fastener may be formed and secured to the surface of a support according to the aboveidentified co-pending application for United States Letters Patent, or by other suitable means. The fastener preferably includes a generally tubular end portion, and may be generally cup-shaped, tubular, or merely include a tubular end as disclosed in the above referenced application for patent. In the preferred embodiment, the end of the fastener includes a plurality of generally radial slits, which facilitate the radial deformation and reverse folding of the circumferential sections between the slits toward the support.

The pilot is then retracted within the anvil or head portion by urging the gun, against the force of the spring, against the fastener. The retracting pilot guides the impacting surface of the anvil into contact with the proximate end of the fastener, disposing the central portion of the impacting face within the tubular end. After seating of the anvil in the fastener, the anvil is next retracted into the body portion of the gun, against the force of a second spring, until it seats. The gun is now ready for firing.

In the preferred embodiment, the plunger or hammer is normally retracted to the rearward portion of the bore of the gun by a piston connected to or integral with the hammer. Depressing of the trigger releases a force of air, through a valve, and forces the hammer violently forward. The hammer impacts the anvil, which deforms the tubular end of the fastener radially outwardly and toward the support, as described hereinabove.

The method of forming a connection between a support and structural member of this invention, includes securing a fastener to the support having a tubular end extending from the support adjacent to the structural member, such as the fasteners disclosed in my above referenced copending application for United States Letters Patent. A supporting member, such as the pilot disclosed hereinabove, is then inserted into the tubular end of the fastener, and the end impacted radially outwardly and toward the support to contact and retain the structural member. In the preferred method, the anvil is positioned against the tubular end of the fastener, while retaining the supporting member within the fastener, and the end of the anvil opposite the fastener is then impacted to deform the fastener end, as described hereinabove. Other advantages and meritorious features will more fully appear from the following description, claims, and accompanying drawings, wherein:

FIG. 1 is a side view, with a portion of the housing broken away of the impacting gun of this invention;

FIG. 2 is a side cross sectional view of the forward portion of the gun, after seating of the pilot in the fastener;

FIG. 3 is a side cross sectional view of the gun shown in FIG. 2, after seating of the anvil in the body portion of the gun;

FIG. 4 is a side cross sectional view of the gun shown in FIGS. 2 and 3 after impact; and

FIG. 5 is an enlarged view of one embodiment of the impacting head portion of the gun.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment of the impact gun shown in FIG. 1 includes a body portion, indicated generally at 22, having a conventional handle or grip 24. The impact gun illustrated in FIG. 1 is pneumatic, having an air pressure inlet line 26 in the handle, and a conventional trigger 28 which operates a valve, not shown, in the handle portion. The details of the pneumatic control of the gun are not shown because this portion of the gun is conventoinal in many tools, including staple guns and other pneumatic impact tools. The trigger is hingedly attached to the body portion of the gun at 30. Depressing the trigger 28 depresses the pneumatic plunger 32, which opens the valve within the handle and permits the air or other gas to enter the body portion of the impact gun of this invention at the rearward end.

The body portion 22 of the gun includes an axial bore 34 which receives the pneumatic piston 36. The piston may be of a conventional design, and includes an O-ring 38 and 40 at either end to prevent the escape of air past the piston, and is secured to the rear end of the plunger means 32 by a threaded screw 42. An end cap 44 is threadably received in the rearward end of the gun to permit removal and replacement of the piston 36. An annular resilient shock ring 46 arrests the forward free travel of the piston within the bore 34. The piston will however stop short of the shock ring in this embodiment, as described hereinbelow. It should be noted that the piston is shown in FIG. 1 forward of the normal or retracted position to permit illustration of the piston in the breakaway view.

The piston 36 is normally retracted to the rearward end of the axial bore 34 adjacent the end cap 44. The rearward end, for the purpose of this description, will be considered adjacent to, or toward the end cap 44. The forward end will be considered adjacent to or toward the work, indicated generally at 48. The introduction of air under pressure into the rearward end of the gun bore 34, by depressing the trigger 28, forces the piston 36 violently forward, toward the shock ring 46. The air in front of the piston is exhausted through the forward exhaust ports 50, and the pressure at the rearward end of the piston is relieved through an exhaust port 52 in the handle. The forward motion of the piston will thus create a lower pressure behind the piston, which causes the piston to return after each stroke, ready for the next stroke.

A plunger or hammer 54 is secured to the piston 36, by the screw 42, to reciprocate with the piston in the bore 56 of the adaptor portion 58 of the housing or body portion of the gun. The adaptor 58 may be secured by any suitable mean to the body portion 22 of the gun, or may be integral therewith. In this embodiment, the adaptor is secured to the body portion by a male threaded portion extending from the flange 60 of the adaptor, which is threadably received in the female threaded flange 62 of the housing 22. The details of the construction of the forward portion of the impact gun of this invention are shown in FIGS. 2 to 5.

The forward or head portion of the gun includes an anvil 64 which is supported for reciprocation in the adaptor body portion 58. In this embodiment, the anvil has an enlarged end 66 which is received in a counterbore 4 68 in the head portion. A threaded retainer 70 is threadably received in the forward end of the head portion which restricts the travel of the anvil and supports its reciprocal motion. The retainer may include a plurality of apertures 72 adapted to receive a spanner wrench, or the like, to

thread the retainer in the head portion.

The anvil 64 is preferably separate from the remainder of the plunger 54, as shown in FIGS. 2 and 3, to absorb the recoil of the impact gun. In this embodiment, the anvil is normally biased toward the forward end of the gun by a coil spring 74 disposed in the eounterbore 68, and tensioned between the enlarged end 66 of the anvil and the rearward wall of the counterbore. The purpose of the spring is to aid in the absorbtion of the shock of impact, and prevent unwanted movement of the anvil which might interfere with the operation of the gun. The anvil must therefore be retracted rearwardly, into the head portion of the gun, prior to impact.

The impact gun of this invention also includes a pilot 76 supported for reciprocation in an axial aperture 78 in the anvil 64. The pilot has an enlarged end portion 80 received in a counterbore 82 in the anvil, and is normally spring tensioned toward the forward end of the gun by a coil spring 84. The coil spring is tensioned between the enlarged end 80 of the pilot and a threaded plug 86 threadably received in the rearward end of the anvil 64.

The end of the pilot 76 is adapted to be received in the generally tubular end of a fastener 88-, such as the fas teners disclosed in my above referenced co-pending application for patent and shown in FIG. 1, or other suitable fasteners. In the disclosed embodiment, the fastener is generally cup-shaped, and is secured to the support 92 by welding, adhesive bonding, or other suitable means. This I embodiment of the fastener is adapted to secure a structural member 94 to the support by deforming the end of the cup-shaped fastener to overlie the adjacent edges of the structural member. The tubular end of the fastener may be provided with slits 96 to facilitate the deformation of the fastener, and the structural member in this embodiment is provided with an aperture 98 which receives the fastener therethrough.

The pilot preferably extends beyond the impacting end of the anvil a distance suflicient to permit location of the gun on the fastener, regardless of the position of the fastener. For example, the fastener shown in the drawings may be located above the impact gun operator, in which case it may be difiicult to orient the gun. In this embodiment, the pilot extends a distance greater than twice the axial depth of the tubular end of the fastener. After the pilot has been located within the fastener, as shown in FIG. 1, the gun is urged forward, thereby retracting the pilot 76 into the anvil 64 as shown in FIG. 2, until the impacting end 90 of the anvil contacts the end of the fastener.

The preferred configuration of the impacting end of the anvil is shown more clearly in FIG. 5. The end of the pilot 76 is disposed within the open end of the fastener, and serves to locate the gun on the fastener and guide the anvil as described hereinaoove, and also to support the sides of the fastener during impact and prevent inward deformation. The impacting end 90 of the anvil includes a central portion 100 disposed within the tubular end of the fastener, including an annular concave surface 102 which engages the inner edge or lip of the fastener. The concave surface smoothly blends into an outer annular surface 104, substantially flat and generally perpendicular to the reciprocating axis of the anvil. The fastener engaging surfaces 102 and 104 are preferably polished to prevent jamming and binding of the fastener during deformation, and in this embodiment the outer annular surface 104 is tapered slightly from the axis, toward the rearward end of the gun, to define a conical surface. A taper of approximately five degrees has been found very satisfactory. The embodiments shown in FIGS.

1 to 4 have not been tapered, and are perpendicular to the axis of the anvil.

After location of the anvil on the fastener, as shown in FIG. 2, the gun is again urged forward, which retracts the anvil 64 into the body portion 53 of the gun, until the enlarged head 66 of the anvil seats against the rearward Wall of the counterbore 68 and the force of the spring 74, as shown in PIG. 3. The gun is now ready for firing, or impact. The trigger 28 is now depressed, which opens a valve in the handle 24 of the gun, and forces the piston 36 and hammer 54 forward, as shown in FIG. 4. The hammer 54 impacts the enlarged end 66 of the anvil, through the coil spring 74, which deforms the tubular end of the fastener. The annular concave surface 102 deforms the fastener radially outwardly and downwardly, and the substantially fiat or slightly conical surface 104 reversely folds the distal ends of the fastener toward the support 92 and tensions the ends of the fastener against the structural member 94, as shown in FIG. 4. As described hereinabove, the piston-36 then retracts the hammer 54 to the position shown in FIGS. 2 and 3, and the gun is ready for the next operation.

What is claimed is:

1. A method of forming a connection between a support and a structural member, including securing a structural fastener to the support having a tubular end extending from the support adjacent the structural member, comprising:

(a) disposing a supporting member within the tubular end of the fastener, and

(b) impacting the end of the fastener radially outwardly and toward the support to contact and retain the structural member on the support.

2. The method defined in claim 1, including the steps of positioning an anvil against the tubular end of the fastener While retaining the supporting member within the fastener, and impacting the end of the anvil opposite the fastener.

3. An impact gun for deforming a generally tubular fastener, comprising: a body, plunger means supported for reciprocation in the body including an anvil adapted to impact the tubular fastener end, and a pilot member supported coaxially within said anvil for shiftable movement with respect thereto, said pliot member normally projecting beyond the impacting end of said anvil to be received within the tubular fastener and retractable upon movement of the anvil toward the fastener to guide the impacting end of the anvil into proper orientation abutting the tubular fastener end.

4. The impact gun defined in claim 3, characterized in that spring means is interposed between said pilot member and the anvil of said plunger means biasing the pilot to a normally extended position disposing the end of the pilot projecting beyond the impacting end of the anvil.

5. The impact gun defined in claim 4, characterized in that said pilot includes an enlarged end opposite the end received within said fastener, said enlarged end received in a counterbore in said anvil, and limiting the travel of the pilot, said spring means disposed within said counterbore and under compression between said enlarged end of the pilot and the anvil.

6. The impact gun defined in claim 3, characterized in that said pilot extends beyond the impacting end of the anvil a distance at least twice the axial length of the fastener.

7. An impact gun for deforming a generally tubular fastener, comprising: a gun body, plunger means in the body including a forward anvil member and a rear hammer member supported in normally spaced apart coaxial alignment in the gun body and independently shiftable therein, said anvil having an impacting end projecting forwardly of said gun body for engagement with the tubular end of the fastener and an enlarged rear end, and said hammer member including means for shifting the hammer forwardly to strike the anvil rear end; a pilot member reciprocably supported coaxially within said anvil member and projecting forwardly therebeyond for reception with the tubular fastener to guide the impacting end of the anvil into abutment against the fastener end; stop means on the body limiting the stroke of the anvil member; and spring means interposed between the body and the rear end of the anvil member biasing the latter forwardly of the gun body.

8. The impact gun defined in claim 7 characterized in that said impacting end of the anvil member includes a central portion adapted to interfit within the tubular end of the fastener and a generally radially outwardly extending surface portion for deforming the fastener upon movement of the anvil.

9. The impact gun defined in claim 8 characterized in that said radially extending surface portion of the impacting end of the anvil is slightly rearwardly tapered to define a generally conical surface.

10. The impact gun defined in claim 9 characterized in that said radially extending surface is tapered at approximately a five degree angle from a plane perpendicular to the anvil axis.

11. The impact gun defined in claim 7 characterized in that said means for shifting the hammer member comprises a fluid operated piston connected to the hammer rear end, and means for controlling the operation of said piston.

References Cited UNITED STATES PATENTS 2,372,029 3/1945 Stair l73133 2,722,918 11/1955 Kimball 173133 1,143,740 6/1915 Wales 29522 1,684,932 9/1928 Weatherhead 29--522 1,947,906 2/1934 Fine 29512 2,583,270 1/1952 Lynall 29512 3,166,828 1/1965 Tupper 29523 3,332,473 7/1967 Frederickson 29--512 CHARLES W. LANHAM, Primary Examiner G. P. CROSBY, Assistant Examiner US. (:1. X.R. 

